20 years is a long time. Consider that 30 years ago there was no mainstream internet or cell phones (just to put things in perspective)
Any occupation that deals with people interaction or business enablement will still be in high demand.
Medical, Technology, and Trade Skills will all be industies in high demand.
If you need a house built, car or plumbing fixed, those things require humans to physically create or repair them.
As the population of this planet swells, more people will need medical treatment and care, of every kind.
Prediction is 9 billion people by 2040, or a 30% increase over the next 20 years.
Technology needs will continue to grow, since most companies are run by technology packages. Key jobs will be in coding, data, security and global systems integration.
It's primarily going to be about Design, not simply how something looks or functions, but how it's produced. The current reality is nearly two-thirds of all jobs are already defined, meaning there is a process already designed and implemented. Many are software assisted. Twenty years ago an Accountant prepared taxes, today its data input and the software prepares your taxes (turbotax). The accountant now functions similar to the fast food worker - follow the designed process. Another example, the new iPhone was designed by 5 people, from form and function to the manufacturing process, while hundreds of thousands are involved in production. That small group defined what many do as a job. That's the future.
Even lawyers cut and paste important documents. Chefs follow recipes. The majority of work in the future will be designed by someone else or software.
Most don't want to admit this because they “love their job,” or it's their “passion,” but that's mostly untrue. Most people wake up and follow directions. Humans are the first robots. But, creating those directions IS the valuable job in the future. Design. Systems. Processes.
Certainly, artificial intelligence and robotics will require support but we already have software engineers, electrical engineers and process and systems analysis. Climate change will require climatologists meteorologists and energy analysts including battery technologists. Related work on fusion will demand physicists. Long-distance transport may begin to be focused on hypersonic sub-space vehicles with the associated demand for aerodynamicists and related specialists. Shortages of food and water will lead to increased levels of conflict and hence the need for defence weapons development as well as agronomists. Have a look at books by Michio Kaku author of Hyperspace and Physics of the Impossible amongst others - but futurologists are always wrong and usually over-optimistic!
